Rational points on quadratic elliptic surfaces

We consider elliptic surfaces whose coefficients are degree 2 polynomials in a variable T. It was recently shown, Kollar and Mella (Amer J Math 139(4):915-936 2017), that for infinitely many rational values of T the resulting elliptic curves have rank at least 1. We prove that the Mordell-Weil rank of each such elliptic surface is at most 6 over Q. In fact, we show that the Mordell-Weil rank of these elliptic surfaces is controlled by the number of zeros of a certain polynomial over Q.